This invention relates to improvements in material handling apparatus and, more particularly, to a mechanism for pushing and diverting objects from conveyors.
It is well known in the prior art of material handling to employ conveyors with moving belts or the like for transporting objects of various sizes and shapes along a path. It is also common practice to utilize diverters along the path for transferring, sorting or distributing the objects at certain points to other locations such as auxiliary conveyors, spurs or outflow chutes. Such arrangements have particular utility in warehouses, factories, truck terminals, shipping rooms, mail bag and courier distribution, and airline baggage systems. In these applications, the diverters may individually, or in combination, push an object at some angle across a conveyor belt, block an object at some angle to the belt so that the belt motion causes the object to slide across the belt, or arrest the motion of and snatch the object from the belt. Additionally, the diverters may employ linear, translatory, or rotary movement of one or more object engaging devices which move through forward and return cycles to unload or remove objects from the belt.
For example, U.S. Pat. No. 3,198,308 to Driesch, et. al., discloses a linear pusher having a paddle fixed at the end of a reciprocating piston rod and parallel to the conveyor belt. Driesch, et. al., also discloses a snatcher having a paddle pivotably attached at one end to a framework and at its end portion to the end of a reciprocating piston rod. U.S. Pat. No. 3,026,988 to Fisk and 4,295,559 to Neal, et. al., are illustrative of air-actuated translatory linkages used to move together with an article along the conveyor while simultaneously shifting the article transversely of the conveyor. U.S. Pat. Nos. 3,083,808 to Graybeal and 4,441,604 to Schlig, et. al., disclose rotary pushers wherein dual paddles are revolved in a rotary motion to engage objects such that the face of each paddle will always remain parallel to the direction of belt travel. Various attempts have been made by each of these patents to upgrade sorting or orienting capability of objects at high speeds by provision of different paddle linkages and their associated drives along with the ensuing geometric motion produced thereby. However, there remains a need in this well-developed art for a diverting pusher which is capable of accomplishing transfer of objects at high rates by controlling the motion and speed of the paddle on a push phase of a cycle for gentle object handling, and then performing the remainder of the cycle rapidly to maximize cycle rate and reduce the spacing between conveyed objects. For instance, when utilizing some prior art devices, some paddles may dwell too long at the end of their forward stroke or operate with time delays which can create jams and missorts. In other cases, the moving mass of the paddle may be at maximum velocity at time of impact with the object with resultant damage or destruction to the objects. These are particularly sensitive drawbacks when diverters or pushers are used in the handling of airline baggage which may vary tremendously in size, shape and fragility.
Accordingly, it is a principal object of the invention to provide an improved pushing and diverting mechanism for unloading a wide variety of objects from a conveyor at a high rate of speed with accuracy and control.
Another object of the invention is to furnish a sorting device which combines linear and articulated movements to deflect objects from a conveyor.
It is a further object of the invention to provide a diverting pusher which will allow for a more gentle removal of objects from a conveyor.
A still further object of the invention is to provide a diverting pusher exhibiting a controlled push cycle to minimize damage to objects being conveyed and an assisted return cycle to reduce spacing between objects being conveyed.
One of the salient features of our invention is the combination of a linear pushing and paddle articulation movement for deflecting objects from a conveyor.
An attendant feature of our invention is a controlled drive arrangement which will decelerate the paddle prior to the termination of the push cycle and accelerate paddle return thereafter.
A further feature of our invention resides in cushioning elements of the diverting pusher.
Another feature of our invention is found in the light weight but rigid construction of the diverting pusher elements which provide the desired high rate of speed with needed stability to resist intermittent impact forces on objects being conveyed.